chore: enable strict: true in root tsconfig (#4683) (#10985)

* test: reproduce #4683 — enable `strict: true` in root tsconfig (failing)

Replace the individual strictness flags (`alwaysStrict`, `noImplicitThis`,
`noImplicitAny: false`, `strictNullChecks: false`) with `strict: true`.
`tsc --noEmit` now reports 351 type errors across packages/.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_016PjJDfAYR1JPdgiQRvvZZy

eddeee888:oss:issue-verify

* chore: add changeset for declaration changes from strict tsconfig (#4683)

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

* fix: satisfy strict mode with graphql 15 typings (#4683)

graphql 15 types Maybe<T> as T | null | undefined, so the CI matrix's
graphql 15 build hits three strict errors that 16/17 don't:
- getPossibleTypes accepts null, which schema.getType() returns on 15
- includeIntrospectionTypesDefinitions skips getNamedType when the field
  type is missing
- graphql-modules preset checks schemaAst.extensions before reading sources

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

---------

Co-authored-by: Claude <noreply@anthropic.com>

Author: eddeee888

.changeset/strict-root-tsconfig.md

@@ -0,0 +1,23 @@
+---
+'@graphql-codegen/cli': patch
+'@graphql-codegen/visitor-plugin-common': patch
+'@graphql-codegen/typescript': patch
+'@graphql-codegen/client-preset': patch
+'@graphql-codegen/testing': patch
+'@graphql-codegen/graphql-modules-preset': patch
+---
+
+Build with `strict: true`, which changes these emitted type declarations:
+
+- `@graphql-codegen/cli`: `mkdirp` returns `Promise<string | undefined>`, and the `require` (`-r`) CLI option's `default` is typed `never[]` instead of `any[]`.
+- `@graphql-codegen/visitor-plugin-common`: `BaseResolversVisitor` and `BaseTypesVisitor` `SchemaDefinition()`/`SchemaExtension()` return `null` instead of `any`.
+- `@graphql-codegen/visitor-plugin-common`: `BaseSelectionSetProcessor.typeCache` is keyed by `Location | undefined`.
+- `@graphql-codegen/visitor-plugin-common`: `SelectionSetToObject.buildSelectionSet` returns `typeInfo` as `{ name: string; type: string } | null`.
+- `@graphql-codegen/visitor-plugin-common`: `getPossibleTypes` accepts `null` as the type, which graphql 15's `schema.getType()` can return.
+- `@graphql-codegen/visitor-plugin-common`: `removeDescription` returns nodes with `description: undefined` instead of `any`.
+- `@graphql-codegen/typescript`: `TsIntrospectionVisitor`'s constructor takes `pluginConfig` as `TypeScriptPluginConfig | undefined`, `DirectiveDefinition()` returns `null` and `ObjectTypeDefinition()` returns `string | null`.
+- `@graphql-codegen/client-preset`: the babel preset accepts `options` as `ClientBabelPresetOptions | null | undefined`.
+- `@graphql-codegen/testing`: `mockGraphQLServer` returns `nock.Scope | null`.
+- `@graphql-codegen/graphql-modules-preset`: a schema without `extensions` (graphql 15) throws the "requires to use GraphQL SDL" error instead of a `TypeError`.
+
+Generated output is unchanged.

packages/plugins/other/visitor-plugin-common/src/utils.ts

@@ -512,7 +512,7 @@ export function separateSelectionSet(selections: ReadonlyArray<SelectionNode>):
 
 export function getPossibleTypes(
   schema: GraphQLSchema,
-  type: GraphQLType | undefined,
+  type: GraphQLType | null | undefined,
 ): GraphQLObjectType[] {
   if (isListType(type) || isNonNullType(type)) {
     return getPossibleTypes(schema, type.ofType);

packages/plugins/typescript/typescript/src/index.ts

@@ -63,7 +63,8 @@ export function includeIntrospectionTypesDefinitions(
   const usedTypes: GraphQLNamedType[] = [];
   const documentsVisitor = visitWithTypeInfo(typeInfo, {
     Field() {
-      const type = getNamedType(typeInfo.getType());
+      const fieldType = typeInfo.getType();
+      const type = fieldType ? getNamedType(fieldType) : undefined;
 
       if (type && isIntrospectionType(type) && !usedTypes.includes(type)) {
         usedTypes.push(type);

packages/presets/graphql-modules/src/index.ts

@@ -23,7 +23,7 @@ export const preset: Types.OutputPreset<ModulesConfig> = {
       );
     }
 
-    if (!options.schemaAst?.extensions.sources) {
+    if (!options.schemaAst?.extensions?.sources) {
       throw new Error(`Preset "graphql-modules" requires to use GraphQL SDL`);
     }
 

tsconfig.json

@@ -15,8 +15,7 @@
     "emitDecoratorMetadata": true,
     "sourceMap": true,
     "declaration": true,
-    "noImplicitThis": true,
-    "alwaysStrict": true,
+    "strict": true,
     "noImplicitReturns": true,
     "noUnusedLocals": true,
     "resolveJsonModule": true,
@@ -52,9 +51,7 @@
       "@graphql-codegen/plugin-helpers": ["packages/utils/plugins-helpers/src/index.ts"]
     },
     "ignoreDeprecations": "6.0",
-    "types": ["node"],
-    "noImplicitAny": false,
-    "strictNullChecks": false
+    "types": ["node"]
   },
   "include": ["packages"],
   "exclude": [